Just a century and a half ago, or 132 years if you really want to be precise, the world witnessed an important historical event. One of the most important construction landmarks in the history of humankind was built – the Home Insurance Building. It was considered by many to be the first skyscraper in the world, although its ten floors might tell us that this label is a bit of a stretch. Skyscraper or not, the Home Insurance Building warrants both respect and remembering by being the first tall structure in the history that’s resting its weight on a steel frame. While this fact is arguable due to a fact that the building rested on granite piers and a brick wall (on one side), the building did set the tone for a new era in construction when builders would turn from concrete and wood to steel.
Since then we had 132 years of lessons learned through examination, trials, and errors. We have had 132 years of uncovering secrets, admiring strengths and witnessing consequences of weaknesses of steel frame constructions. In this article, we will present you what we are, as constructors specializing in steel fabrication field, know and hold to be important when aiming for successful steel frame construction.
Steel is the most widely used building material for its many agreeable properties that have been mentioned countless times by countless sources. And the advantages of steel framed buildings over those with wooden frames are many. However, it is important to remember that buildings are what is being discussed (and made), and they, no matter the material, will be as sturdy, flexible and good as their foundations.
Going not deep enough might mean less durability in case of an earthquake or high winds; going too deep, money and time will be wasted – given the fact the success of a building is largely measured in its economic viability. This could be a bad way to start. The proper way to start is to first take a good look at what the state, the city, or whoever has the authority over construction endeavors, demands from a building in order to be approved.
The second step is to examine the land on which the building will be built as well as general conditions of the area that might have additional demands from the structure. These conditions can be a wind, or a susceptibility to landslides to name the most obvious ones.
The third step in a foundation construction process is taking a decision on a foundation type. This will mostly depend on the building and its frame. For example, lighter buildings that are being built on the land that could be called stable and where no extreme weather can be expected would usually have concrete piers for their foundation, similar to the Home Insurance Building. In situations where the buildings are heavy, located on not so stable land, or in an area where strong winds are to be expected, the usual approach would be to go for a massive concrete slab.
Paying attention to steps pertaining to the legal constraints of the construction and making sure to start with the right materials are the only way to get yourself on the way towards having a successful steel frame construction.
Another important thing to keep in mind is weaknesses of steel frame construction. Although steel is probably the best material for a building we have at our disposal right now, and steel frames the most reliable to go for, neither steel nor its method of assembly and combination are completely infallible. In fact, steel has two widely know points of weakness that need to be addressed in order to have a successful steel frame construction. These are corrosion and fire.
While corrosion is not something we worry about, it is important to have anti-corrosion protection for parts that are expected to be exposed to harsh atmospheric conditions. Galvanization is the most commonplace step taken with this goal in mind.
Another great danger to any steel frame construction is fire, as, depending on various conditions such as the type of steel or the type of flame, steel beams can start losing their strength and load capacity by as much as 50% at a temperature of around 500 degrees Celsius or higher. The most widely used type of fire protection, especially in the UK, US and Canada is the film intumescent coating. The coating material behaves similarly to a regular paint at room temperatures, however, when needed, changes its properties and turns into a heat insulation material through a series of complex chemical reactions. It envelops the steel beam or any other structural piece coated in film intumescent coatings. These types of insulation materials can provide up to 2 hours protection ins a case of fire, and they are crucial for safety.
Ductility and flexibility are two properties of steel which are generally very good, turn into sort of a double-edged sword when fires are put into the equation as the softening of main supporting structures can cause them to collapse under their own weight as the heat intensifies. Failing to take these flaws of steel frames into account when constructing a building can result either in a project being rejected by the local authorities, or lead to serious damages in property or even endanger lives.
To sum up, in order to erect successful steel frame structures it is important to be aware of some bad properties of steel and know how to address them.